Re: AdditionalType was: audiobook options in objects

Richard, I don't think that we can declare that each bibliographic 
description describes a single, uncomplex type. To begin with, there is 
that library bugaboo "kit" in which the item in question is 
simultaneously multiple types:
    a kit with multiple parts, each of which is a different thing (a 
puppet, a book, some crayons)

There is also:
    a book with an included CD

There are also many libraries that do not create separate records for 
the hard copy and digital:
    record for a book with an additional link to the online copy

And almost none create separate records for hardcopy and paperbacks.

The upshot is that we will need to handle multiple types in a single 
description. These are also an "AND" relationships, at least in relation 
to the bibliographic data. How would this be done?

[And in another thread, as I say, I do not consider a "CD" to be a 
further typing of a creative work, since I would not say that a "CD" is 
a type of musical work.]

kc


On 2/13/13 6:57 AM, Richard Wallis wrote:
> Hi All,
>
> I’ve pulled this out of the audiobook thread as I think it is generally
> applicable to several areas of our discussions.
>
> Karen’s points below highlight several points relevant to this, which I
> will try to clarify.
>
> This emerged from the audiobook thread as audio book is a good example
> of something in our domain of multiple types – a creative work, possibly
> a book, with a file format (WMA, MP3, etc), and a physical form (CD,
> cassette tape, etc.).  That thread has moved on and we proposing a new
> sub-type of CreativeWork – AudioBook, which I agree with.  For the
> purposes of examples in this email am presuming that proposal has been
> accepted.
>
> Starting with Karen’s second question:
>
>     /Second, it still isn't clear, however, if you have multiple
>     associatedMedia fields, e.g. A, B and C, whether that means that you
>     have that CW in three different media, or if you have the CW in a
>     single medium that is defined as A+B+C.
>     /
>
>
> She is referencing multiple instances of a property, however I believe
> it is the same question for multiple types.
>
> It is an AND relationship.
>
> The turtle syntax is really helpful for envisioning multiple types:
>      <http://example.com/1234>
>          a schema:Audiobook, pto:Windows_Media_Audio, pto:Compact_Disk;
>
> Which can be unpacked as:
>      <http://example.com/1234>
>          a schema:Audiobook;
>          a pto:Windows_Media_Audio;
>          a pto:Compact_Disk;
>
> Which can be read as:
>      <http://example.com/1234> is the identifier for a thing which is
>          a Audiobook and,
>          a Windows_Media_Audio, and
>          a Compact_Disk
>
> If you want to describe something (an audio book) that is available in
> several formats, you are describing relationships between different things.
>
> Against my better judgement and dipping into FRBR language to explain
> it....
>
> You would have the description of an Expression, of type Audiobook, with
> links to instances (Manifestations) for each format. Each instance would
> be a combination of Audiobook and Compact_Disc; Audiobook and DVD;
> Audiobook and Cassette; etc.
>
> Check out the examples library
> A0<http://www.w3.org/community/schemabibex/wiki/Examples/mylib/A0>
> (Expression) and its related instances (Manifestations)
> A1<http://www.w3.org/community/schemabibex/wiki/Examples/mylib/A1> and
> A3<http://www.w3.org/community/schemabibex/wiki/Examples/mylib/A1> to
> see how this might be encoded.
>
>
>
> Moving on to how we encode multiple types for a thing there are a couple
> of issues to address.
>
> Firstly, the differences between RDF (Turtle), RDFa, and Microdata.
>
>   * RDF is the most obvious – as per the above example you just keep
>     adding type statements as required.
>   * RDFa add the type URI to the ‘typeof’ attribute:
>
>         <div vocab="http://schema.org/"
>              typeof="Audiobook
>     http://www.productontology.org/id/Compact_Disk">
>
>   * Microdata is a little more difficult as the microdata standard does
>     not natively support multiple types.  To overcome this limitation
>     Schema introduced the addtionalType property so that they could
>     encode this concept using microdata, thus:
>
>         <div itemscope itemtype="http://schema.org/Audiobook">
>              <link itemprop="additionalType"
>     href="http://www.productontology.org/id/Compact_Disk">
>
>
> The fact that the microdata solution uses additionalType as the property
> name introduces the impression that the other type(s) are somehow
> subordinate.  Maybe it would have been better to have ‘alsoOfType’ as a
> property name.
>
> The important effect of this approach is that there is no relevance in
> the order of their declaration.  For instance a librarian may describe
> an audiobook on CD in microdata thus:
> <div itemscope itemtype="http://schema.org/Audiobook">
>
>       <link itemprop="additionalType"
>     href="http://www.productontology.org/id/Compact_Disk">
>
>
> Whereas a retailer may describe the same thing as:
> <div itemscope itemtype="http://www.productontology.org/id/Compact_Disk">
>
>       <link itemprop="additionalType" href=" http://schema.org/Audiobook">
>
> These are both valid and equivalent to each other.
>
>
> ~Richard
>
>
> On 09/02/2013 20:09, "Karen Coyle" <kcoyle@kcoyle.net> wrote:
>
>     Owen, I take your point: additionalType seems to be sub-typing
>     CreativeWork, not adding information about the product. I vaguely recall
>     having been warned about additionalType -- that it is not often used and
>     seems to be tricky. Here's the definition of "aT":
>
>     "An additional type for the item, typically used for adding more
>     specific types from external vocabularies in microdata syntax. This is a
>     relationship between something and a class that the thing is in. In RDFa
>     syntax, it is better to use the native RDFa syntax - the 'typeof'
>     attribute - for multiple types. Schema.org tools may have only weaker
>     understanding of extra types, in particular those defined externally."
>
>     Richard posted this in an email: [1]
>     "
>     Sticking with the Product Ontology approach for a moment ­ an audiobook
>     in WMA on a cd would just be a combination of multiple types thus:
>       > http://schema.org/Book
>       > additionalType: http://www.productontology.org/id/Audiobook
>       > additionalType: http://www.productontology.org/id/
>     Windows_Media_Audio
>       > additionalType: http://www.productontology.org/id/ Compact_Disc
>       >
>
>     First, I think that "/associatedMedia" in CreativeWork looks to be a
>     better fit for this. It is defined as: "The media objects that encode
>     this creative work. This property is a synonym for encodings."
>
>     Second, it still isn't clear, however, if you have multiple
>     associatedMedia fields, e.g. A, B and C, whether that means that you
>     have that CW in three different media, or if you have the CW in a single
>     medium that is defined as A+B+C. I believe that Richard's example above
>     was the latter. You seem to be concerned about encoding the former.
>     Surely we need to be able to distinguish between them. I believe that
>     means moving toward item or offer-level description for the different
>     encodings. I can't think of any other way to make it clear.
>
>     kc
>

-- 
Karen Coyle
kcoyle@kcoyle.net http://kcoyle.net
ph: 1-510-540-7596
m: 1-510-435-8234
skype: kcoylenet

Received on Wednesday, 13 February 2013 14:04:24 UTC